Enable page load test on linux

Break out page load test into its own target on Linux.

Also, build the reliability_tests target on Linux.

Neither of the new targets have trybots or buildbots yet, however, they do work for me locally.

BUG=19085
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=26530

[huanr, 2009-09-17 23:41:54]

LGTM. 

Lei: when we get the bot that builds reliability_tests on Linux, in addition to
build the target, we want to run it with a few sample URLs include "about:crash"
for each cycle. We want to ensure that the test can report crashes if they
exist.

[Evan Stade, 2009-09-17 23:45:03]

Just so I understand correctly, why do we need that?

1) isn't that essentially the point of the PageLoadTest.Reliability uitest?
Perhaps the same bot could run the linux_page_load_uitest target as the
reliability tests.
2) don't all runs have *some* crashes? It would be pretty suspicious if the
total crash count dropped to 0 per million

[huanr, 2009-09-17 23:55:39]

For chromebot running with continuous build, each cycle may run 50-60k URLs and
there could be no crashes.

On 2009/09/17 23:45:03, Evan Stade wrote:
> Just so I understand correctly, why do we need that?
> 
> 1) isn't that essentially the point of the PageLoadTest.Reliability uitest?
> Perhaps the same bot could run the linux_page_load_uitest target as the
> reliability tests.
> 2) don't all runs have *some* crashes? It would be pretty suspicious if the
> total crash count dropped to 0 per million

[Evan Stade, 2009-09-18 00:00:43]

for outside observers, the plan is indeed to use PageLoadTest.Reliability (I
simply misunderstood him)

[Lei Zhang, 2009-09-18 00:26:24]

LGTM